Welding method and welding equipment

Abstract

A welding method, which subjects a surface to be built-up of an elongated workpiece to a build-up welding process along a longitudinal direction of the workpiece, includes a step for forming a build-up layer on the surface to be built-up by supplying a filler metal to the surface to be built-up along the longitudinal direction and by applying a laser beam thereto to melt the filler metal. A refrigerant is supplied to the surface to be built-up of the workpiece, during the step for forming the build-up layer.

What is claimed is: 
     
         1 . A welding method for subjecting a surface to be built-up of an elongated workpiece to a build-up welding process along a longitudinal direction of the workpiece, the welding method comprising:
 a step for forming a build-up layer on the surface to be built-up by supplying a filler metal to the surface to be built-up along the longitudinal direction and by applying a laser beam thereto to melt the filler metal;   wherein a refrigerant is supplied to the surface to be built-up of the workpiece, during the step for forming the build-up layer.   
     
     
         2 . The welding method according to  claim 1 , wherein
 in the step for forming a build-up layer, the filler metal is supplied to the surface to be built-up while the laser beam is applied thereto.   
     
     
         3 . The welding method according to  claim 1 , wherein
 the refrigerant is supplied to the workpiece at a position forward an application position of the laser beam on the workpiece, in a relative movement direction of the application position with respect to the workpiece.   
     
     
         4 . The welding method according to  claim 1 , wherein
 the refrigerant is water.   
     
     
         5 . The welding method according to  claim 1 , wherein
 the workpiece is rotated around a rotation axis along the longitudinal direction, during the step for forming the build-up layer.   
     
     
         6 . The welding method according to  claim 1 , wherein
 in the step for forming a build-up layer, the filler metal is supplied to the surface to be built-up by forming a filler metal layer by thermally spraying or applying a filler metal to the surface to be built-up; and   after the filler metal layer is formed, a laser beam is applied to the filler metal layer along the longitudinal direction to again melt the filler metal of the filler metal layer.   
     
     
         7 . The welding method according to  claim 6 , wherein
 the refrigerant is supplied to the workpiece at a position forward an application position of the laser beam on the workpiece, in a relative movement direction of the application position with respect to the workpiece.   
     
     
         8 . The welding method according to  claim 6 , wherein
 the refrigerant is water.   
     
     
         9 . The welding method according to  claim 6 , wherein
 the workpiece is rotated around a rotation axis along the longitudinal direction, during the step for forming the build-up layer.   
     
     
         10 . A welding equipment for subjecting a surface to be built-up of an elongated workpiece to a build-up welding process along a longitudinal direction of the workpiece, the welding equipment comprising:
 a supporter that supports the workpiece;   a filler-metal supply unit that supplies a filler metal to the surface to be built-up of the workpiece;   a laser irradiator having a laser oscillator, and a laser emitter that emits a laser beam oscillated by the laser oscillator toward the workpiece supported by the supporter;   a longitudinal motion drive that relatively moves the laser emitter along the longitudinal direction with respect to the workpiece supported by the supporter; and   a refrigerant supply unit that supplies a refrigerant to the surface to be built-up of the workpiece supported by the supporter.   
     
     
         11 . The welding equipment according to  claim 10 , wherein
 the refrigerant supply unit has a nozzle for ejecting the refrigerant; and   the longitudinal motion drive relatively moves the nozzle, together with the laser emitter, along the longitudinal direction with respect to the workpiece supported by the supporter.   
     
     
         12 . The welding equipment according to  claim 11 , wherein
 the nozzle is positioned forward the laser emitter in a relative movement direction of the laser emitter with respect to the workpiece.   
     
     
         13 . The welding equipment according to  claim 10 , further comprising a rotational motion unit that rotates the workpiece supported by the supporter around a rotation axis along the longitudinal direction. 
     
     
         14 . A welding equipment for subjecting a surface to be built-up of an elongated workpiece to a build-up welding process along a longitudinal direction of the workpiece, the welding equipment comprising:
 a filler-metal-layer forming unit that forms a filler metal layer by thermally spraying or applying a filler metal to the surface to be built-up;   a supporter that supports the workpiece with the filler metal layer formed thereon;   a laser irradiator having a laser oscillator, and a laser emitter that emits a laser beam oscillated by the laser oscillator toward the workpiece supported by the supporter;   a longitudinal motion drive that relatively moves the laser emitter along the longitudinal direction with respect to the workpiece supported by the supporter; and   a refrigerant supply unit that supplies a refrigerant to the surface to be built-up of the workpiece supported by the supporter.   
     
     
         15 . The welding equipment according to  claim 14 , wherein
 the refrigerant supply unit has a nozzle for ejecting the refrigerant; and   the longitudinal motion drive relatively moves the nozzle, together with the laser emitter, along the longitudinal direction with respect to the workpiece supported by the supporter.   
     
     
         16 . The welding equipment according to  claim 15 , wherein
 the nozzle is positioned forward the laser emitter in a relative movement direction of the laser emitter with respect to the workpiece.   
     
     
         17 . The welding equipment according to  claim 14 , further comprising a rotational motion unit that rotates the workpiece supported by the supporter around a rotation axis along the longitudinal direction.